MINERAL RESOURCES OF THE STATE OF NEW YORK 265 



1 Clinton limestone, upper layer, Lockport. U. S. Geol. Surv. Bui. 522 



2 Clinton limestone, middle layer, Lockport. Idem. 



3 Clinton limestone, lower layer, Lockport. Idem. 



4 Lockport dolomite, south of Niagara Falls. William Massing's quarry. H. 



Ries, analyst, N. Y. State Mus. Bui. 44. 



5 Lockport dolomite, quarry I5 miles east of Lockpoit. D. H. Newland, 



analyst. Idem. 



6 Guelph dolomite, Gates, near Rochester. Snow's quarry. D. H. Newland, 



analyst. Idem. 



7 Guelph dolomite, Rochester. Copeland quarry. D. H. Newland, analyst. 



Idem. 



8 Bertie Waterlime, Buffalo. Quarry of Buffalo Cement Co. 



9 Bertie Waterlime, near Leroy, Genesee county, Howell farm. D. H. New- 



land, analyst. Idem. 

 ID Manlius limestone. Split Rock, Onondaga county. Quarry of E. B. Alvord. 

 Idem. 



11 Manlius limestone, Split Rock, Onondaga county. Quarry of Solvay Process 



Co. Idem. 



12 Manlius limestone, cement rock, Jamesville, Onondaga county. Quarry of 



E. B. Alvord. Idem. 



Devonian limestones. The more important calcareous deposits 

 among the Devonian formations are comprised within the Helder- 

 bergian group, the Onondaga Hmestone and the Tully Hmestone. 

 The higher Devonian strata, represented by the Portage and 

 Chemung formations with the Catskill equivalents of eastern New 

 York, are devoid of limestone beds of workable size and character; 

 the Tully occupies the most southerly position of all the commercial 

 limestones in the area west of the Catskill mountains. 



The Helderbergian group is made up of several distinct strati- 

 graphic units or formations inclusive of the Coeymans, Kalkberg, 

 New Scotland and Becraft, all of which are essentially calcareous 

 in nature. They are restricted in area to the eastern part of the 

 State, the Coejrmans alone extending as far as Onondaga county to 

 the vicinity of Manlius. The outcrop east off Oneida county lies 

 along the highland south of the Mohawk river jwhich becomes the 

 Helderberg mountains in Albany county, where the limestones have 

 a thickness of 200 feet. Here the outcrop swings around to the 

 south, parallel with the Hudson river, along the west side of which 

 it continues through Greene county to Kingston. An outlier of the 

 Greene county area is found to the east of the river on Becraft moun- 

 tain near Hudson. The limestones in many places are in close 

 association with the upper members of the Cayugan group, with 

 which they are stratigraphically continuous and closely allied in 

 character. Along the Hudson valley the group attains a thickness 

 of about 200 feet, of which the Coeymans constitutes 50 feet, the 

 New Scotland 100 feet, and the Becraft 35-40 feet. The Coeymans 

 is a heavily bedded, dark gray limestone well adapted for building 



